Monodisperse platinum nanoparticles with controlled size were synthesized by polyol synthesis and supported on γ-Al2O3, SiO2 and carbon nanotubes (CNT) by the colloid deposition method. The average size of Pt nanopar...Monodisperse platinum nanoparticles with controlled size were synthesized by polyol synthesis and supported on γ-Al2O3, SiO2 and carbon nanotubes (CNT) by the colloid deposition method. The average size of Pt nanoparticles in colloidal solutions and on supports were determined by TEM images and from XRD patterns. The size of Pt nanoparticles supported on SiO2 and CNT determined from XRD patterns is in a good agreement with size obtained from the TEM analyses. There were shown that no agglomeration and size changing of Pt nanoparticles on these supports were observed. All these findings illustrate that the method of colloid deposition allows one to obtain catalyst with monodisperse platinum nanoparticles of controlled size deposited on different supports without changing the nanoparticle’s size and morphology.展开更多
Copper-based catalysts were widely used in the heterogeneous selective hydrogenation of ethylene carbonate(EC),a key step in the indirect conversion of CO_(2) to methanol.However,a high H_(2)/EC molar ratio in feed is...Copper-based catalysts were widely used in the heterogeneous selective hydrogenation of ethylene carbonate(EC),a key step in the indirect conversion of CO_(2) to methanol.However,a high H_(2)/EC molar ratio in feed is required to achieve favorable activity and the methanol selectivity still needs to be improved.Herein,we fabricated a series of Pt-modulated Cu/SiO_(2) catalysts and investigated their catalytic performance for hydrogenation of EC in a fixed bed reactor.By modulating the Pt amount,the optimal 0.2Pt-Cu/SiO_(2) catalyst exhibited the highest catalytic performance with99%EC conversion,over 98%selectivity to ethylene glycol and 95.8%selectivity to methanol at the H_(2)/EC ratio as low as 60 in feed.In addition,0.2Pt-Cu/SiO_(2) catalyst showed excellent stability for 150 h on stream over different H_(2)/EC ratios of 180-40.It is demonstrated a proper amount of Pt could significantly lower the H_(2)/EC molar ratio,promote the reducibility and dispersion of copper,and also enhance surface density of Cu+species.This could be due to the strong interaction of Cu and Pt induced by formation of alloyed Pt single atoms on the Cu lattice.Meanwhile,a relatively higher amount of Pt would deteriorate the catalytic activity,which could be due to the surface coverage and aggregation of active species.These findings may enlighten some fundamental insights for further design of Cu-based catalysts for the hydrogenation of carbon–oxygen bonds.展开更多
文摘Monodisperse platinum nanoparticles with controlled size were synthesized by polyol synthesis and supported on γ-Al2O3, SiO2 and carbon nanotubes (CNT) by the colloid deposition method. The average size of Pt nanoparticles in colloidal solutions and on supports were determined by TEM images and from XRD patterns. The size of Pt nanoparticles supported on SiO2 and CNT determined from XRD patterns is in a good agreement with size obtained from the TEM analyses. There were shown that no agglomeration and size changing of Pt nanoparticles on these supports were observed. All these findings illustrate that the method of colloid deposition allows one to obtain catalyst with monodisperse platinum nanoparticles of controlled size deposited on different supports without changing the nanoparticle’s size and morphology.
基金supported by the National Natural Science Foun-dation of China(22022811,U21B2096 and 21938008)the National Key Research&Development Program of China(2018YFB0605803).
文摘Copper-based catalysts were widely used in the heterogeneous selective hydrogenation of ethylene carbonate(EC),a key step in the indirect conversion of CO_(2) to methanol.However,a high H_(2)/EC molar ratio in feed is required to achieve favorable activity and the methanol selectivity still needs to be improved.Herein,we fabricated a series of Pt-modulated Cu/SiO_(2) catalysts and investigated their catalytic performance for hydrogenation of EC in a fixed bed reactor.By modulating the Pt amount,the optimal 0.2Pt-Cu/SiO_(2) catalyst exhibited the highest catalytic performance with99%EC conversion,over 98%selectivity to ethylene glycol and 95.8%selectivity to methanol at the H_(2)/EC ratio as low as 60 in feed.In addition,0.2Pt-Cu/SiO_(2) catalyst showed excellent stability for 150 h on stream over different H_(2)/EC ratios of 180-40.It is demonstrated a proper amount of Pt could significantly lower the H_(2)/EC molar ratio,promote the reducibility and dispersion of copper,and also enhance surface density of Cu+species.This could be due to the strong interaction of Cu and Pt induced by formation of alloyed Pt single atoms on the Cu lattice.Meanwhile,a relatively higher amount of Pt would deteriorate the catalytic activity,which could be due to the surface coverage and aggregation of active species.These findings may enlighten some fundamental insights for further design of Cu-based catalysts for the hydrogenation of carbon–oxygen bonds.
